Control for differential drive



Oct. 8, 1957 MUELLER 2,808,739

CONTROL FOR DIFFERENTIAL DRIVE Filed April s, 1953 SSfieets-Sheet 1 r40 47-77 o 0 4w 29 7 2 INVENTOR- I 052 b {V'ZzcZZah' I/VEYS- vx k Oct. 8, 1957 MUELLER 2,808,739

CONTROL FOR DIFFERENTIAL DRIVE Filed April s, 1953 s Sheets-Sheet 2 JNVENTOR;

022 0 MaelZel 1 FTp/YA V -Oct. 8, 1957 o. MUELLER 2,808,739

. CONTROL FOR DIFFERENTIAL DRIVE Filed April 3, 1953 3 Sheets-Sheet 3 9 I e52 f z- -i 2 0 4. F j I a 92 7 e INVENTOR.

0Z2? Ma i/en BY Utliwd Scams, Patent G 2,808,739 P CONTROL'FORDIFFERENTIALDRIVE" Otto Mueller; Dem-born, Mich". A licafionn rils;mssgseriama. smash Tommie; (CL-744411) This'inventio'n relateslto differential .drives for vehicles; antifpa'rticula'rlyio a differentiallvehiele drive havihga. positive drive and .Tdifierential. action a .on .th'e'two: driven axles;

Diflicnlty has been experiencedintthe. pastiwh'enem ployingpinion. and side; gears. :in'. the-drive .for .the two driven ;a'x-1es.' The .difie'rentiallwas necessary :totperrnit one wheeltotoperateat a difierent speed fromihe-othelp whenltheuveliicle. was drivenraroundcurves, over rough terrain, or when difierent diameter tireswere-used. When suchdifierential was providedlon the; axles, .the .drive- -to* one'wheel was interrupted 'asthe other. wheelspumwhenit lost traction: due. .to .mud; ice,.. and like-conditions.- Many attempts. have. been .made'. .to eprovide meanshforlocking the two driven axlestogethen While-maintaininga' difie'rential action .therehetween,-. but 11p to the present time no known structure hasebeenprovided.which'satisfactor-il accomplishes suchlcombination of actions.-

Tlie present invention .pertain swto the application-wot a fluidm'echa-nisin to. the differentialaassembly, so-corw structed 'iand 'applied .theneto that complete-- control 0th the driving of-the two driven .shatts ismaintained at all tithes, whicli'applies .torque tmboth wheels whi-le-per-P emitting a diifrential'actionto occur therebetweemwhensuch action -is required. The fluid mechanism embodies?-;

a vane' type rotor. mounted withina compression iringtand suitably ported tooperate. onthe :oilrnormal-ly-providedinI-the dilfe'rential housing The ringis-ported-to admit theioil to' within cavities. provided between the!-ring-.andthe'rotonwhere it'is. operated on.by the -vanes;- whichi applies ressure .to .the .oil..and .forms :a -loelc-between the rotor and the ring. 5 In this .arrangementgttherotor andLring'forni an automatic .clutch for lockingethe dif ferential case and the .operation-ofnthwp'inion :gears relative tothe side gears. .Positive-controlmean's m'aya; beuprovided for at determining; the. oil pressure; which-- embodies a1springloaded-relief valve; When 'the"-*pres=-'- sure of "the oil'lopensrthe relief. valve -the dilferentialw action may occur between the-two side gears The 'sar'ne z resultmaybe obtained by permittingea leakage ofatheit oil under pressure,- which will occur when the pres'sure has reached'a predetermined amount. 'Theleakagevwilli permit" the differential. action .betweenthe two side gears when relatively' moved at slow-'speed,-but'when one of a the wheels attemptsto. spin, thefast relative movement" between the rotor. and=ring,-:which isattempted to occur, willbe blocked by the inability of any further rate in oil" leakage. With this..construction,-the differential mech anismfiunctions inthe-normal manner to permit one wheel: to rotate at adifierent speed relative to the other? wheeLwhilethe vehicle is being driven but willprevent either of the wheels from-spinningrelative 'to the other- Whfiel. in view of the-locking or clutching of the rotor with.the ring of the'fluid actuated mechanism. This relationship causes 'bothwheels to=have approximately.- the same. torque applied.- thereto in' all-conditior'1s--of:-- operation ofsthe wheels. g

Accordingly, the main objects of the invention are: to

. Patented. Och-8,

apply. torque to-'b oth axles of a-vehicle at-all times-re-"- gardless of the difference in traction on the-wheels while" permitting diflerential movement therebetwee'n; ?topro,- videat fluid} actuated mechanisrnin thedifieren'tiahasserriblywhich'is effectiveto lock-=bothof the driven: axles together 'sothat torquemay he applied -to both? axles at all timeswhile perrnittingdiflierentialmovemenh therehetween;- to *employ the 1 fluid inthe housing ofa2: difierential foroperating-a fluid actuated clutch" which maintains a driving relationbetween'the'- two axles wh'ile permitting a 'difi'erential movement therebetween; to secure one e1ement-of-afluid' actuated-- clutch-"to'the" side gear of a difie'rentiahassembly andtheother-ele'ment thereof-to -.t he--difierentia-l case which permits diflie'rential movement between wheels -when required but-which locks the side gear and -case to have" torque-applied :in sub-*- stantially equal amounts to I the -driven axles irrespective of--the difierencein traction;- on the wheels driventhereby;= to :providea fluid aetua-teddocking-member between the operating relements ofa vdiifereritiab to control 'the' dif ferential movement of the axles byithe amouribof -fluid whichis by-passedfrom i the mechanism,=- so-- constructed that; the mechanism iseifective'to -provide--the confrohin both the forward or reverse movement-of the yeh'icle,- arid,=-' in =-gener al, to provide-a =control mechanism fora" dif ferentiaL of: a vehicle which is -simplein construction; positive in operation; andeconomicaloffimariu-facture?- Other object-sand -fea-tures" of =novelty of the inventionwill bespecifically pointed out 1 or will I become appare'nt whenrrefierring for a better understanding of the inven" tion, to the followingadescription;: taken in conjuhetion with the accompanying drawing-sgwhereinz' Figure l isa-- sectional view -throu'gh -a -differentialassembly, havingza fiuidactuated mechanism applied"? thereto embodying features of: the pres'ent invention;

-Fig.2 is --an-.-enlar ged; -brokenview of 'a portion'of-l' the structure illustratedin Fig. =1;

, Fig; 3 is asectional: view of the structure illustrated in Fig.2, taken on the-line-3'3=thereof;

Fig. .4-is' an enlarged, broken sectional vi'ew "of tlfe" structure illustrated in Fig. 3-,'-* taken on' the line" 4"'4-=' thereof;

Fig. 5 is a broken view of structure"; similar to tlia't f illustrated in- Fig. 1, a showing another form which' the invention may assume; and

Fig. G'iS a-section-al view of the-structureilliistrated in 5, taken on the line 66 thereof."

A diflferential housing 10 -=has a stubsh'attll mounted?- therein on bearings-l3t The stub 'shafthas a coupling 14 on the outer end which-is connectible' to" the' dr i shaft of avehicleand is sea-ledio the end 'of'the hou ingby a-sealing element-15% The-stub" shaft" 11" has a? pinion 16 on the forward end; the-teeth of which engage"-' the teeth of a ring gear=17 secured'toa flange' ls pr'cije ing fromone side of adifferential-case+'1 by suitab bolt assemblies20.- The case-19"has a hollnw' st'ern 21". which is mounted in- 1 abear-ingvZk- The 'ni'ain they of the case-has-a threaded en'd 24'-to"whiclia thieafied cap. 25-is secured. The capwZS h-asa hollow st in alignment with the stern-:21* Wl-rich is mouhted bearing 27 The bearings are"-supported'in drical apertures 28 in the 'housing 10, enclo'sed in the: semicylindrical-apertures in caps-29.-'- A pair of-studs 'il-ls secures the caps 29' on the housing:10=in position to secure the bearings 22- and '27- inthe" apertures28 E'ridl'l caps 32, threadedimo the apertures' forrned by thehousing -10-and 'caps 29, secure the case assembly agaiii'st' lateral displacement: Afte'r adjustment, dockingclamps- 33 are secured on the caps 29- by: studs 34'; with tlie' ends-* 35 of w the clamps;- extending Jin one of a mianwmr f apertures:36--providedin the caps ffii The body 23 of the case 19 has a shaft 37 extending therethrough, forming oppositely disposed stub shafts on which a pair of pinion gears 38 are mounted. A pin 39 extends through an aperture in the differential case and through the shaft 37 near one end thereof. The shaft37 forms the driving member through which torque is applied to the driven shafts of the vehicle. The pinions 38 on the shaft 37 form a floating key which produces the driving relation between the shaft 37 and the side gears 41 and 42. While differentials are provided having only the two pinions 38 driven from a single shaft 37, in the present arrangement a pair of additional stub shafts, not illustrated, are mounted on a collar 43 through which the shaft 37 extends, which collar carries the stub shafts in 90 relationship to the shaft 37 for projection through apertures in the body 23 of the case 19. After the stub shafts have been inserted in the apertures in the body 23, and those in the collar 43, similar pins 39 retain the shafts in assembled relation. The drive also occurs from the case to the additional stub shafts and pinions 38 which are mounted thereon. It is to be understood that the shaft 37 and the two stub shafts and collar 43 are often provided as a unit spider, with the four pinions 38 mounted directly thereon. In such an arrangement, the body 23 of the case is split parallel to the stub shafts and bolted together after assembly.

The 'side gears 41 and 42 have teeth thereon disposed in mesh with the teeth of the pinions 38 and are provided with a splined opening 44 for engaging splines on the end of the axle shafts 40 in driving relation thereto. The side gear 41 is rotatably mounted in the case 19, with a thrust washer 45 therebetween for taking the thrust from the pinions 38. The side gear 42 has a splined shoulder 46 and a bearing surface 47, the latter of which is journaled in the stem 26 of the cap 25 which forms a part of the case 19 for relative rotation therein.

The splined shoulder 46 on the side gear 42 has a rotor 48 secured thereon in splined engaged relation as illustrated in Fig. 2. The rotor is provided with a plurality of slots 49, herein illustrated as twelve in number, although it is to be understood that the number of such slots may be varied. The slots receive vanes 51 mounted for movement outwardly and inwardly therein. The bottom of the slots 49 is enlarged to form a well 52 at the inner end of each of the vanes 51 in which oil will collect and apply a pressure to the end of the vanes to force them outwardly as the oil bleeds past the wall of the case and the plate 63, which will be described hereafter. Notches 53 are provided in the sides of the vanes for receiving resilient means 54 which urge the vanes outwardly so that the outer ends of the vanes will engage the inner surface of the ring 57 at low R. P. M. The resilient means 54 herein illustrated is an O-ring, a spring wire formed in a circle, or a coiled wire disposed annularly. The resilient means isso proportioned as to exert an outward force on the vanes at all times. Apertures 55 extend inwardly from the periphery of the rotor between the slots 49, communicating with laterally disposed apertures 56 near the inner edge of the rotor. Thus, the fluid trapped by a vane will be forced into the apertures 55 and 56.

A compression ring 57 is mounted within the end of the body 23 of the case 19, secured in position by a plurality of locking studs 58. The internal surface 59 of the ring has two oppositely disposed compression surfaces 61 and 62 generated in such form as to maintain uniform pressure on the trapped oil.

A control plate 63, which is made of bronze or like bearing material, is mounted within the body 23 of the case 19 against a shoulder 64 thereof, against which the rotor 48 and ring 57 are retained by the cap 25 of the case. The plate 63 is secured to the ring 57 by a pin 65 to maintain the ring and plate in a desired angular position relative to each other. The plate 63 forms a thrust surface for the shoulder 66 of the side gear 42, the inner surface 67 of which forms a bearing on the annular surface 68 of the side gear 42. A plurality of apertures 69 are provided through the plate 63 in position to communicate with the apertures 56 in the rotor 48. The plate 63 also has elongated apertures 71 and 72 therein located substantially on the center of the compression surfaces 61 and 62. The apertures 71 and 72 form inlet ports for admitting the oil within the differential housing to between the peripheral face of the rotor and the compression surfaces 61 and 62. The oil is picked up by the vanes 51 which are retained in contact with the compression surfaces at all times, either by the spring means 54, by centrifugal force, or by the fluid under pressure within the walls 52. t The vanes force the oil into the restricted area at one or the other end of the compression surfaces 61 and 62, depending upon which direction the rotor or case is being relatively driven, and the oil thus pressurized is forced through the apertures 55 and 56 as long as leakage occurs from the orifice 56 between the cap 25 and the plate63 and between the surface 47 on the side gear 42 and the stem 26, which thereby lubricates the surface 47. When the relative rotation between the rotor 48 and ring 57 is substantial, the oil under pressure, not being able to escape from the aperture 56 at any degree of volume, will cause a lock to occur between the rotor 48 and ring 57, thereby applying substantially equal torque to both of the side gears 41 and 42 and driving the vehicle axles and wheels at substantially the same speed. It is only when the relative rotation between the rotor 48 and the ring 57 occurs at low speed, such as produced when one wheel moves faster than the other when the vehicle is rounding a turn, that the small amount of trapped oil under pressure will be expelled through leakage, permitting the rotor to turn relative to the ring 57 without locking and permitting a differential movement to occur between the axle shafts and wheels.

It is to be understood that the same action occurs between the rotor 48 and ring 57 when the vehicle is reversed from that occurring when the vehicle is driven forward. It is further to be understood that in either direction of motion of the vehicle, the movement between the rotor 48 and ring 57 in rotation is relative so that the same locking relationship therebetween occurs whether the rotor is the driven element or whether the ring 57 is the driven element in either the forward or reverse movement of the vehicle. Thus, it will be apparent that if one wheel of the vehicle is on an icy, wet, muddy, or otherwise slippery surface, that even though the traction is removed from the wheel, torque will still be applied in substantially equal amounts to both wheels so that the wheel having traction can move thevehicle from the slippery surface. It will be also apparent that when a wheel driven by the presently used differentials has no traction, the motor is no longer effective as a brake for the vehicle. When using the fluid actuated mechanism of the present invention, the engine is available at all times for braking the vehicle. Thus, in all conditions of operation of the vehicle, positive torque is applied to both axles and wheels while a differential action may occur therebetween.

A further form of the invention is illustrated in Fig. 5, that wherein the fluid actuated mechanism is placed on the ring gear side of the assembly rather than on the opposite side thereof, as illustrated in the foregoing figures.

cylindrical opening 74 therein, enlarged for receiving and supporting a large roller thrust bearing 75. A cap by the splined end of an axle shaft when inserted therein. The rotor has slots 49 and vanes 51 therein operating in a ring 57, the same as illustrated in Fig. 3. Between the vanes 51, laterally disposed apertures 56 In this arrangement, a housing 73 has a semiaregprovidedt communicating. with. an:; aperture-1-82 in threaded. plugs 81 locatedv midway .between the vanes: 51. A ball 84 isdisposed beneath eachofthe threaded plugs 853and. are urgedthereagainst byisprings' 85. The spring? pressed balls,- form. checkvalves, permitting fluid. to pass throughithe passageway, 82 fromrtherperipheral edge of the rotor and preventing the fluid from passing outwardly through the apertures A plate=86;.made of bronze or other} bearing material, is mounted against a shoulder of the case 76, with a rearwardly extending annular flange 87 which forms a bearing with the outer surface of a hub 88 on the side gear 89 which is supported in a bore 91 of the case 76. The plate 86 has an inner annular surface 92 journaled on the rotor and an outer face abutting the side of the rotor 78 and the compression ring 57 as illustrated in Fig. 6. A plurality of apertures 93 are provided through the plate 86 in communication with the apertures 56 through the rotor body. The fluid passing from the aperture 56 through the apertures 93 builds up a pressure within the pocket 94 which has a substantially greater effective area than that at the engaging portions of the ring and rotor therewith so that such greater pressure will urge the plate 86 into sealed relation to the sides of the rotor and ring, to thereby prevent leakage of fluid under pressure therefrom. An aperture 95 extends from the well 94 to a recess 96 in the case 76. A ball 97 is supported in the end of the aperture 96 by a spring 98, the pressure of which may be regulated by a pair of hollow plugs 99 which may be adjusted and locked relative to each other. The pressure applied to the ball regulates the pressure on the oil which must be reached before it is relieved so that a diflerential action can occur between the shafts to which the torque is applied.

A second bearing plate 101 is mounted on the forward side of the rotor 78, having an annular flange 102 which is disposed in bearing relation to the shouldered end 103 of the rotor 78. The plate has a face 104 which abuts the outer side of the compression ring 57 and rotor 78 against which it is retained by a nut 105 when threaded upon the diflerential case 76. Elongated apertures 71 and 72 extend through the plate 101, fixed in relation to the ring 57 by the pin 65 to function in the same manner as the plate 63 of Figs. 1 to 4. The fluid operated mechanism thus provided functions in the same manner as that illustrated and described in Figs. 1 to 4, the difference between the two structures residing primarily in the use of leakage in the structure of Figs. 1 to 4 for permitting the differential action between the driven shafts, while in the structure of Figs. 5 and 6 leakage is prevented from occuring and the by-passing of fluid past the ball 97 is relied upon for permitting the differential action to occur between the shafts. Further, the fluid mechanism illustrated in Figs. 5 and 6 is on the opposite side of the assembly from that illustrated in Figs. 1 to 4, being on the side carrying the ring gear of the assembly. It will be noted in this arrangement that the adjustable thrust mechanism 110 illustrated in Fig. 1 heretofore applied to back up the ring gear of the differential assemblies is eliminated since the thrust resulting from the operation of the teeth of the pinion 16 on the teeth of the ring gear 17 is substantially at 90 to the large hearing 75 which is of sufficient strength to back up and take such thrust.

What is claimed is:

1. In a differential having a side gear, a plate on said side gear rotatable relative thereto, a rotatable element of a pump fixed relative to said side gear to rotate therewith, and a compression element of said pump rotatablewith said plate which is laterally shiftable relative thereto and to said rotatable element, said plate having an aperture therethrough for delivering fluid into the area between the rotatable element and compression element in which the fluid is received and compressed.

2. In a:xiitferentialohavingm:sidergear, a "pump having one element onrsaid-side gear,pa-p latez;between said pump and side gear enclosing one side face of said pump, a case'iaboutsaidpump and "said side gear enclosing: the

. opposite" side. face of said 'pump,"said plate having a passageway therethroughtor'de'livering fluid to the pump which produces pressure thereon, the fluid under .pressure when delivered between the: plates and .side gear forcing; said plate against" saidpump and said-pump agai-nstsaid casing-to thereby-reduce the leakage *occuring therebetween as the relative movement between said gear and case increases.

3. In a differential having two relatively rotatable elements, a compression ring having a plurality of compression areas secured to one rotatable element, a rotor member secured to the other rotatable element, means for compressing fluid in said areas when said rotor member and said compression ring are relatively rotated, a plate abutting one side of said rotor and compression ring, and subject to differential fluid pressures from said areas to press said plate against said rotor and compression ring.

4. In a differential having two relatively rotatable elements, a compression member secured to one rotatable element, a rotor member secured to the other rotatable element, means for compressing fluid when said rotor member and said compression member are relatively rotated, a plate abutting one side of the compression member and rotor member and having a passageway therethrough to conduct fluid to an intake area between said compression member and rotor member, said plate being subject to differential fluid pressures resulting from relative rotation of said members to press said plate against said rotor member and compression member and reduce the leakage therebetween.

5. In a differential having two relatively rotatable elements, a compression member secured to one rotatable element, a rotor member secured to the other rotatable element, means for compressing fluid when said rotor member and said compression member are relatively'rotated, and a plate abutting one side of the compression member and rotor member and having a passageway extending therethrough through which fluid passes into the intake area between said compression member and rotor member, said plate being arranged to rotate with said compression member and subject to pressure resulting from relative rotation between said members whereby it is pressed laterally against said compression member and rotor member. a

6. In a differential having pinions and a side gear, said side gear having a shoulder, a plate on said side gear adjacent to said shoulder, pump elements having 'a rotatable part fixed relative to said side gear and engaging said plate, said plate abutting one face of said pump elements, and being subject to differential fluid pressure resulting from operation of said pump to press said plate against said pump elements, a case on said differential having a portion abutting the opposite face of said pump elements, said plate having an intake aperture through which fluid is delivered to said pump elements.

7. In a differential having a side gear, relatively movable pump elements having one part rotatable with said side gear, a case in said differential supporting another element of said pump for rotation therewith, and a plate abutting one side face of said pump, the opposite side face of the pump abutting said case, said plate having fluid delivery apertures therethrough, the elements being so related that axial thrust of the side gear applies a clamping force to said plate to clamp said pump elements between the plate and case thereby decreasing fluid leakage therebetween and increasing the pressure in the fluid operated on by said pump elements.

(References on following page) References Cited in the file of this patent 2,247,410

7 UNITED STATES PATENTS 473,444 Barney Apr. 26, 1892 2562'177 1,156,819 Rich Oct. 12, 1915 2 571 0 3 1,466,320 West Aug. 28, 1923 2 637 275 1,997,788 Friedell Apr. 16, 1935 2 2,035,514 Staats Mar. 31, 1936 2,206,907 Loughridge July 9, 1940 499 048 2,207,310 Ballamy July 9,1940 10 .8 I Ross July 1, 1941 Schlicksupp Mar. 26, 1946 Kloss Feb. 20, 1951 1 De La Hitte July 31, 1951 Roth Oct. 9, 1951 McFarland .'May 5, 1953 FOREIGN PATENTS Great Britain Jan. 18, 1939 

